Apparatus for producing a packaging container comprising a container body of thermoplastic material and a metal foil lining inserted into the container body

ABSTRACT

Apparatus for providing a thermoplastic container with a metal foil lining by shaping the metal foil lining as it is inserted into the container by forming overlapping folds of the foil so it will conform to the shape of the liner walls of the container.

A ril 17, 1973 A. R. RAUSING 3,728,196 I APPARATUS FOR PRODUCING APACKAGING C AlNER COIPRl I A CONTAINER BODY OF THERMOPLASTIC MA I AL ANDA ME AIN IL LINING INSERTED INTO THE CONT 7 ER BODY Original Filed 9,1968 2 Sheets-Shut l I l A WV ,1 I! II IIIIII ll 1/ 1111111111!!! 4 a .1

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4 APPARATus FOR PRODUCING A PACKAGING CONTAINER COuPRIsINC A CONTAINERBODY OF THERMOPLASTIC MATERIAL AND A METAL FOIL LINING INSERTED INTO THECONTAINER BODY Original Filed Sept. 9, 1968 I 2 Shasta-Sheet z.

3,728,196 APPARATUS FOR PRODUCING A PACKAGING CONTAINER COMPRISING ACONTAINER BODY OF THERMOPLASTIC MATERIAL AND A METAL FOIL LININ GINSERTED INTO THE CONTAINER BODY Anders Ruben Rausing, Blentarp, Sweden,assignor to Sabrefina SA, Fribourg, Switzerland Original applicationSept. 9, 1968, Ser. No. 758,433, now Patent No. 3,616,033. Divided andthis application Mar. 17, 1971, Ser. No. 125,348 Claims priority,application Sweden, Sept. 25, 1967, 13,129/ 67 Int. Cl. B31f 1/00 US.Cl. 156-443 4 Claims ABSTRACT OF THE DISCLOSURE Apparatus for providinga themoplastic container with a metal foil lining by shaping the metalfoil lining as it is inserted into the container by forming overlappingfolds of the foil so it will conform to the shape of the inner walls ofthe container.

This application is a divisional application of my earlier filed parentapplication Ser. No. 758,433 filed Sept. 9, 1968, now US. Pat.3,616,033.

This invention is concerned with a method of producing a packagingcontainer comprising a container body of thermoplastic material and ametal foil lining inserted into the container body. The invention isfurther concerned with a device for carrying out the operation inaccordance with the above and also with a packaging container producedin accordance with this method.

It has for a long time been the objective within the packaging industryto develop types of package that solve in the best way the specificproblems which arise within packaging technology. A throw-away packageshall e.g. be inexpensive but it shall also be well suited to itscontents, so that it protects the controls in the best way bothmechanically and otherwise. The package shall further appeal to thecustomer, i.e. the contents shall be easily accessible when the customerwants to make use of them. It shall further have a low weight and bewell suited to storage in available spaces. These requirements thatmodern packages have to meet have resulted in the development of a greatnumber of different types of package, each of Which has been suited toone special type of contents.

Within the canning industry, package materials other than sheet metalhave not been used very much up till now, which material exhibits manyproperties suited to canning. Sheet metal is e.g. very impermeable andhas very satisfactory mechanical strength. The drawbacks of sheet metalpackaging are that it is comparatively expensive and besides so strongmechanically that sheet metal packaging containers cannot be openedwithout the use of special aids in the shape of tin openers or keys.Glass packages in the shape of jars or bottles have so far been thepredominant method of packaging for aerated liquids, e.g. aerateddrinks, beer, etc. The impermeability of glass is certainly remarkable,but glass packaging is heavy, expensive and comparatively easy todamage, and attempts have therefore been made to find a method ofpackaging which will replace sheet metal and glass for the above groupsof products. The solutions which have so far been put forward in thisconnection entail a transition to sheet metal or glass packages whichhave a lesser thickness. Attempts have also been made in many places touse plastic packages as an alternative to sheet metal or glass packages,but these attempts'have come to nothing as a result of the fact thatknown plastic materials that "United States Patent 3,728,196 PatentedApr. 17, 1973 can be used economically have an impermeability that istoo unsatisfactory for use for either canned goods or aerated drinks. Inthe case of canned goods, oxygen diffuses into the package, as a resultof which the contents are oxydised, and in the case of aerated drinks,carbon dioxide diffuses out of the package.

It can be stated that there exists a need for a cheaper, lighter andeasier-to-open packaging container that has suificient impermeability,and this invention gives directions concenrning such a packagingcontainer as well as the method of its production.

The invention is thus concerned with a method of producing a packagingcontainer which comprises a container body of thermoplastic material anda metal foil lining inserted into the container body. The invention ischaracterised by a blank, conveniently of round shape, of a metal foilcoated with thermoplastic material being, by means of a tool, pressedinto the said container body and by the plastic coating of the metalfoil, at least along a continuous joint, being heat sealed to thecontainer body around its opening. The invention is furthercharacterised by the blank, or roundel, being made to assume, throughbeing folded, the shape of the container body, and by the said foldingand shaping being brought about by the blank, through the application ofvacuum, being sucked against the tool which has longitudinal groovesthat facilitate the formation of the folds, the grooves being capable ofconnection to a source of vacuum.

Packaging containers which have been produced in accordance with theinvention have the advantages of the conventional cans, i.e. they havevery satisfactory impermeability as a result of the incorporation of ametal foil layer in the wall of the container. They can also be madesufliciently stilf mechanically by surrounding the packaging containerby e.g. a sleeve of cardboard or plastic. The package will be lighterthan earlier conventional preserve packages, and also considerablyeasier to open, since it is possible to break through the walls of thepackage with a much simpler tool, or the package may quite simply befitted with an opening device that makes a special opening toolunnecessary.

One constructional form will be described in the following by referenceto the attached diagrammatic drawings, of which FIG. 1 shows two viewsof a vacuum tool in partial section, FIG. 2 shows the thermoplasticcontainer body which has been placed in a holder and is ready to receivethe metal lining. FIG. 3 shows how the metal lining is inserted into thecontainer body, FIG. 4 shows a cross section of the completed packagingcontainer and finally FIG. 5 shows a flat blank which is to be insertedinto the conical top portion of the container.

For the sake of clarity, we will first of all define the terminologyused as regards the packaging container itself. The term container bodythus refers in this case to a pre-produced hollow body of thermoplasticmaterial. The layer of metal foil inserted into the container body istermed lining, the container body and the lining together forming apackaging container that may in a suitable manner be provided with somekind of closure covering the opening of the container.

FIG. 1 shows a partial section of a folding tool 3 which consists of acylindrical portion and a curved bottom portion. The tool has a numberof pleating grooves 5 which extend parallel along the cylindricalportion and towards the centre part of the bottom portion, which groovesthrough ducts 9 are connected to the inside of the tool, which in turnis connected to a source of vacuum or of gas under pressure by means oftube 7. The upper portion of the tool shown is covered by a sheet 6around the outside edge of which there is fitted a ringshaped weldingunit 8. There is on the curved bottom porthe tool a central suction hole10 by means of which the tool is capable of attaching to itself flatblanks.

The insertion of the lining into the container body is elfected in thefollowing way: the pre-produced container body 11 shown in FIG. 2 isinserted into an outer holder 13 which supports the sides of containerbody 11, the outward-folded flange 12 of container body 11 beingpreferably made to rest on the top of holder 13. The material from whichthe lining is to be made consists of preproduced roundels 1 of metalfoil, preferably aluminium foil, coated with thermoplastic, the coatingconsisting of a layer 2 of polyethylene or polypropylene, or somevarnish that is suitable for lamination.

The lining operation is begun by the inside of tool 3 through tube 7being connected to a source of vacuum and by the tool being thereafterbrought into contact with a pre-produced lining blank. This ispreferably done by the tool being lowered towards a pile ofplastic-coated roundels of aluminium foil. When the centre portion ofthe tool has come into surface contact with the uppermost roundel in thepile, this is attached by suction to the tool by means of suction hole10. Tool 3 can now be lifted up and will than take with it the uppermostroundel in the pile. While the inside of the tool 3 is still connectedto a source of vacuum, the tool is positioned above the container body11 inserted into holder 13 and is lowered into this. When tool 3 islowered down into container body 11, the roundel of metal foil is foldedup against the outside of the tool and is sucked into the grooves in thetool. This suction of the roundel 1 of metal foil into grooves 5 isaccompanied by the formation of folds in the roundel of metal foil, thedesign of grooves 5 being such that the folds formed are even.

When the roundel 1 of metal foil has been sucked against tool 3 as shownin FIG. 3a and has been sucked into grooves 5 in tool 3, as shown inFIG. 3b, and when tool 3 has been brought to the final position shown inFIG. 30, the inside of tool 3 is connected to a source of gas underpressure through the tube 7. Instead of being sucked into grooves 5, thelining 1 is now forced out of the grooves into a position shown in FIG.3d, i.e. the lining forms a largely even inside coating in containerbody 11. In order that the contact between lining 1 and the inside ofcontainer body 11 may be further improved, it is an advantage if, inconjunction with lining 1 being pressed out of grooves 5 through theaction of gas under pressure, tool 3 is rotated by means of shaft 14.This rotation of the tool also results in the extraction of the tool outof the container body being easier to achieve without the lining beingwithdrawn as well.

While the tool 3 is still inside container body 11, the plastic layer 2of lining 1 is welded to container body 11 along a continuous sealingzone shown at 17 by the dashed line in the vicinity of the opening ofcontainer body 11. This welding or sealing of the plastic layer 2 oflining 1 to container body 11 is carried out with the aid of thering-shaped sealing unit 8 fitted around the upper part of tool 3. Thewelding operation may be effected by heat being produced in the sealingunit, and by this heat being then conducted by way of the metal foillayer to the plastic layer and to the wall of container body 11, and byso much heat being supplied that the plastic layer 2 of the lining isfused with the inner surface of the container body 11. The heat requiredfor this fusion may also be produced by means of ultrasonic waves or byhigh-frequency methods. The choice of the welding method used depends onthe properties of the material. Thus, it may sometimes be diflicult toconduct a sufiiciently large quantity of heat through a metal foillayer, since the cooling area of the metal foil is large. Highfrequencywelding would also seem not to be directly applicable to the sealing ofa laminate comprising a layer of metal foil, since the heat quantityproduced tends to be concentrated in the layer of metal foil. The mostsuitable welding method in the present case is probably ultrasonicwelding, i.e. mechanical oscillations of ultrasonic frequency aregenerated in sealing unit 8 which is then brought into contact with thelaid-up material layers which are to be welded together; or also impulsesealing, i.e. sealing with the aid of a unit that by means of impulsesof current is heated to sealing temperature. The heat generated in theplastic material shall be suflicient for the materials to be weldedtogether into an impermeable and homogeneous joint.

The packaging container, i.e. the container body 11 provided with thelining, that has been formed can be closed by a thin sheet of materialbeing placed over the opening of the container and welded to the flange12 of the container body. In order that this cover shall have the sameimpermeability as the rest of the packaging container, it should alsocontain a layer of metal foil. In order to enable the cover material tobe heat sealed to the packaging container along the flange 12, the covermaterial is provided with a coating of plastic which can be weldedagainst the upper side of flange 12. In order that such welding of thecover material should be possible, it is naturally necessary that themetal foil lining 1 in the packaging container should not extend abovethe plane of the opening of the container, since any metal foil that mayhave been folded out over flange 12 would make it impossible to effect aseal between the cover material and the said flange.

The closure of the packaging container may also be elfected by theopening of the container body 11 being covered, by means of a conical orhemispherical part that has a flange corresponding to flange 12 of thecontainer body, being placed over the opening of the container body insuch a way that the flanges coincide. The two flanges can now be weldedtogether, a bottle-shaped container being obtained.

In order that the impermeability characteristics of the packagingcontainer should not be made worse, the packaging container with theconical upper part 16, shown in FIG. 4, should be provided with a lining15 of metal foil, which is sealed to the conical part 16 alongcontinuous weld joints shown at 17 and 17 by dashed lines, the conicalpart being preferably of the same material as the container body 11. Themetal foil lining 15 can in the case of the packaging container shown inFIG. 4 be made as a flat circular sector consisting of a metal foilcoated with plastic. By means of the edges of the sector shown in FIG. 5being brought together, a conical shape is formed that can be insertedinto the conical'upper part 16. It is also of importance here that themetal foil lining should not be allowed to project beyond the flange 18.

The constructional example of the invention shown here is only intendedas an illustration of the idea behind the invention, and it is thuspossible, within the framework of the invention, to modify both theshape of the container body and the shape of the part 16 covering theopening of the container body. The invention has proved to be veryvaluable and is the first solution that we know of, of the problem ofobtaining the same impermeability characteristics in a packagingcontainer of plastic as in packaging container of sheet metal or glassknown earlier.

What is claimed is:

1. Apparatus for producing containers having a thermoplastic body and aninner metal foil lining secured to said body by a thermoplastic coatingthereon, comprising a hollow mandrel-like tool having a plurality ofgrooves extending axially along the cylindrical outer surface thereofand towards the center at the bottom spherical portion thereof, saidgrooves being provided with a plurality of openings communicating withthe interior of said mandrellike tool, means for supporting athermoplastic container body having a cyclidrical body portion, aspherical bottom portion, the inner contours of which correspond ingeneral with the outer contours of said mandrel-like tool and a topcircular opening, means for moving said tool into the thermoplastic bodyfor pressing a metal foil thereinto,

said metal foil having a thermoplastic coating on that side which facesthe container body, means for applying a vacuum to the interior of saidtool and to the openings in the grooves so as to shape the metal foil tothe outer surface of said tool and to the container body by creatingaxial folds in the foil in the grooves of said tool, means for applyinggas pressure to the interior of said tool and to the openings in thegrooves, means for withdrawing and rotating said tool about its axis aspressure is applied to the openings in the grooves for releasing themetal foil from said tool while overlapping at least a portion of eachof the axial folds therein and means for heat-sealing at least a portionof the thermoplastic coating to the thermoplastic container.

2. Apparatus. as claimed in claim 1 wherein said mandrel'like tool isprovided with an opening at the bottom of the bottom spherical portionthereof for receiving and holding a metal foil lining when vacuum isapplied thereto.

3. Apparatus as claimed in claim 1 wherein said heat- References CitedUNITED STATES PATENTS 2,958,266 11/ 1960 Wilson 9336.01 3,291,87412/1966 'Negoro 425388 X 3,244,524 4/1966 Decker et a1 156-73 X1,945,243 1/ 1934 Watkins et al 93-36.01

ALFRED L. LEAVI'IT, Primary Examiner D. A. SIMMONS, Assistant ExaminerU.S. Cl. X.R.

